In recent years, there have been proposed and developed various hydraulically-operated vane rotor equipped variable valve timing control (VTC) devices, capable of locking a relative angular phase of a vane rotor (a camshaft) to a housing (an engine crankshaft or a timing sprocket) at a predetermined relative angular phase between a maximum phase-advance position and a maximum phase-retard position by engagement of a lock pin during an engine stopping period, thereby improving a startability of the engine.
One such valve timing control apparatus has been disclosed in Japanese Patent Provisional Publication No. 2013-119842 (hereinafter is referred to as “JP2013-119842”), corresponding to U.S. Pat. No. 8,789,505, issued on Jul. 29, 2014. The valve timing control apparatus disclosed in JP2013-119842 is configured to permit two adjacent hydraulic chambers (that is, a phase-retard hydraulic chamber and a phase-advance hydraulic chamber), arranged circumferentially adjacent to each other and defined on both sides of a vane, to be communicated with each other at a maximum phase-retard position of the vane rotor, prior to locking the vane rotor. This increases a fluttering motion of the vane rotor, caused by positive and negative alternating torque transmitted from the camshaft due to spring forces of valve springs, thereby enabling the vane rotor to be moved to the predetermined relative angular phase (i.e., the lock position) rapidly.